# Relationship history for MSHA mine 2102393

Current hierarchy: **Darwin  Johnson → Bowman Const. Co., Inc. → Cedar Rapids Jaw Crusher**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Bowman Const. Co., Inc. → Cedar Rapids Jaw Crusher; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Darwin  Johnson  et al → Cedar Rapids Jaw Crusher; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Darwin  Johnson  et al → Bowman Const. Co., Inc.; 1950-01-01 to current/open; source msha-controller-operator-history